The present invention relates to a photogrammetric device for use in aircraft or spacecraft. The device produces orientation data, the course or flight path of the aircraft or spacecraft, and a digital terrain representation by the use of photosensitive semiconductors arranged in lines or rows. The device is generally of the type described in my copending application Ser. No. 194,430 (the '430 application) filed Oct. 6, 1980, the relevant portions of which are incorporated by reference.
The above '430 application relates to a sensor device which includes an arrangement of at least three spaced-apart sensor lines or rows A, B, C which are parallel to one another. Each of the sensor lines is periodically scanned to provide successive line images or an "image strip". The sensor lines thus produce simultaneously three image strips corresponding to the terrain over which the device is flown. However, each of the image strips is produced from a different perspective. A large number of identical terrain points are determined in the three image strips by means of digital image correlation, and the identical points form rays with the corresponding centers of perspective of the image strips. The intersection of all the rays associated with the three image strips, with a few ground control points, allows a three-dimensional terrain model to be determined, as well as the orientation parameters of the individual line images.
The above determinations can be made either line by line, by tying in each line image as it is produced to the then existing terrain model, or by the simultaneous determination of all orientation parameters of one image strip section, by means of known methods in analytical photogrammetry and balancing calculations.